During a spacewalk at the International Space Station on Tuesday, NASA ran into a bit of a problem. The Italian astronaut, Luca Parmitano, suddenly found that his helmet was flooding with water. In the weightless atmosphere of space, these globes of liquid floated instead of sinking down into the suit and being absorbed. This prompted NASA to quickly cancel the mission, hurrying Parmitano back into the ISS.

The threat wasn't overrated. The ISS soars 250 miles above the planet, so any type of potential hazard has to be dealt with swiftly and immediately. If something had gone wrong in this case, medical assistance would have been difficult to attain in a timely fashion. It takes a while during a spacewalk for astronauts to enter the space station once more and take off their gear.

When the water first started entering his helmet, Parmitano thought it was his drink bag leaking. He quickly drained it, hoping it would solve the issue; yet the liquid kept coming.

NASA quickly called off the spacewalk before 9 a.m. and had Parmitano return to the ISS. By the time that his helmet was removed, about 1 to 1.5 liters of water had collected inside his suit. Since there isn't a lot of absorptive material inside the helmet, a continued leak could have ended in disaster. Lead spacewalk officer Karina Eversley admitted that Parmitano could have been at risk of drowning if the water had continued to fill the suit, according to Reuters.

Walking out into space is one of the most dangerous things an astronaut can do while in orbit. They have to face the harsh conditions of space, knowing that if anything goes wrong, it could be complicated by the fact that they're not in a location that can easily receive help.

"You know, you are embarking in your own little spaceship, and so it has to be fully operational and as safe as the one you are leaving before you commit to it," said Tom Jones, a former astronaut and veteran of four shuttle flights and three spacewalks, in an interview with USA Today.

Currently, officials are examining exactly what might have caused the leak. It's possible that the astronaut's liquid-cooled undergarment could have been the source, but investigations are ongoing.